CGTalk - Robo Arm rigging

Turrok

03-25-2003, 10:08 AM

http://turrok.republika.pl/cgtalk/1.jpg http://turrok.republika.pl/cgtalk/2.jpg
My first post here :buttrock:
Sorry for my English

I'm trying to rig the arm of my robo model. One part of robo causes me some problems.
I wanted the upper arm part connected to "BONE1" to rotate on x-axis just like "BONE2".
I've tried to wire "BONE2" x-axis to "BONE1" x-axis and it worked, but after creating IK Chain for arm, it stopped.
All methods are welcommed, constraints, scripts, maybe some different approach.
I'm sure, that this is quite easy task, but those are my first steps in animation with IK and bones system.

Please help. :shrug:

Turrok

michaelcomet

03-25-2003, 11:51 AM

In MAX bones always have the X axis pointing down their length. You might be able to go the Hierarchy Panel, "Affect Pivot Only" and then rotate the local axis so it points a different way, but that really won't buy you anything...

One you apply IK you won't be able to script/read that value since max likes to hide the ik solution values...which sucks.

Another alternative would be to apply IK from the shoulder all the way to the wrist...then set up IK limits on the shoulder so it doesn't rotate as much.... or do two ik chains and get fancy with making the first target move somehow relative to the hand target.

Turrok

03-26-2003, 08:58 AM

Thanks for answer michaelcomet.
I've tried with one IKChain from arm to the wrist and after limiting rotation joints it still acted weird...
I'm working on two IKChains method, but for now with no results :thumbsdow

I've made some simple animations to show what I want to achieve.

Desired effect (http://turrok.republika.pl/cgtalk/desired.avi)
Unwanted "default" effect (http://turrok.republika.pl/cgtalk/unwanted.avi)

Turrok

michaelcomet

03-26-2003, 12:31 PM

Well if you set limits on the joints that should work...that first joint should be unlimited/unable to move and locked on the axis you want.

Another option although more work to animate is simply to make that first joint FK, so you have to manually rotate it, and then the rest IK...of course that means you'll have to do the work of keeping it lined up. But I'm still pretty sure if you set limits in the Hierarchy Panel of the IK it should work.....

Turrok

03-27-2003, 07:35 AM

I've tried again with one IKChain for all arm bones. I've locked IK limits for unwanted bone rotations. To test it I've started to move my IKChain helper in one axis and it started to slide where my first bone of IKChain is (and the whole bones with it). I also loose needed control on my IKSwivel point.

For now I leave it as it is and animate it manually.
Thanks for help anyway.:rolleyes:

Turrok

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